Connection boxes bearing retaining devices for maintaining contact, which can receive electric contacts, are described in applications U.S. Pat. No. 5,746,624, U.S. Pat. No. 6,068,512, U.S. Pat. No. 5,190,476 and U.S. Pat. No. 5,836,796.
According to the different embodiments, a connection box generally comprises a first part in which sockets are arranged and possibly a second part in the form of a frontal grid.
An electric contact, for example such as described in patent application FR-2,818,027, can come to be housed in these sockets.
Each socket generally comprises an elastic element provided with a bearing surface cooperating with a shoulder created at the level of the electric contact. Thus, in its rest position, the bearing surface of the elastic element is supported against the shoulder and is opposite the contact outlet. The elastic element is sufficiently flexible and comprises an appropriately designed surface, joined to the bearing surface to permit its flattening during introduction of the electric contact.
The electric contact can have different shapes, notably a parallelepiped body, the shoulder being created at the level of an opening provided at the level of the surfaces or formed directly by a part of the rear surface of said body.
In FIGS. 1A and 1B, elastic elements 10 of a connection box are shown in detail, each of them having a bearing surface 12 that can cooperate with a shoulder 14 of an electric contact 16.
According to the different embodiments, the bearing surface and the shoulder have planar surfaces. These planar surfaces assure an absorbing of axial forces but not shearing force. Moreover, there is always some play between the contact and the socket, so that this play combined with the non-absorbing of shearing forces can generate a rapid deterioration of the retaining device.
Document U.S. Pat. No. 4,969,841 proposes an improved retaining device comprising three different bearing surfaces that cooperate with a shoulder and two wings created at the level of the electric contact. Even though this device obtains a better absorption of forces than the devices previously mentioned, it is not entirely satisfactory since it requires a relatively complex form of the elastic element and a particular form of the electric contact, having two wings that project relative to the body.
The present invention also seeks to alleviate the disadvantages of the prior art by proposing an improved retaining device for maintaining an electric contact in a connection box, of simple design, obtaining a better absorption of both axial and shearing forces.